|Two large twenty yr.old oak trees adawn the front our house. Branches that die and fall off are dressed with a substance that looks like raisens clustered together. At the base of trees I use red mulch to dress decorate. For the past two yrs. large unsightly mushrooms have been growing. I have used a fungicide,|
|The growths on the branches sound like galls. Galls are irregular plant growths which are stimulated by the reaction between plant hormones and powerful growth regulating chemicals produced by some insects or mites. Generally they are caused by wasps and there's no real control for them. As a rule, though, they don't really harm the tree - they just look unattractive.
The mushrooms are more of a concern. They are popping up because of decomposing organic matter. It could be from the mulch you've put beneath your trees or they may be growing because some of the roots beneath the soil surface are dying. Although a fungicide will kill the mushrooms, it won't keep new ones from forming. As long as there is decomposing organic matter, they will continue to pop up. Try raking away the mulch material from one area beneath the tree to see if more mushrooms develop. If not, they are being caused by the mulch itself. If new mushrooms pop up from the bare soil, it indicates some tree roots are dead or dying.
Hope this information helps you determine just what might be causing those mushrooms!